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On August 26, 1998, the B29 Standards committee agreed via letter ballot to consolidate and revise the following three chain standards: ASME B29.6, Steel Detachable Link Chains, Attachments, and Sprockets; ASME B29.19, Agricultural Roller Chains, Attachments, and Sprockets; and ASME B29.25, Open Barrel Steel Pintle-Type Conveyor Chains, Attachments, and Sprockets. The new Standard was designated ASME B29.300, and entitled Agricultural, Detachable, and Pintle Chains, Attachments, and Sprockets. The new Standard has been assigned to Subcommittee 4 - Agricultural, Detachable, and Pintle Chains.

The 1998 revisions of B29.6, B29.19, and B29.25 have been designed to integrate the agricultural-type chains found in each of these three Standards.

B29.6 - Steel Detachable Link Chains, Attachments, and Sprockets

Detachable link power transmission chains have been used almost exclusively by agricultural implement manufacturers for power transmission and conveyors on manure spreaders, corn pickers, planters, hay rakes, potato diggers, elevators, and many other types of machines.

The first steel detachable link chain was manufactured in 1897. This steel chain is made from special analysis steel strip, and is heat treated after forming to withstand wear and provide strength and toughness.

Early in 1950, agricultural equipment manufacturers realized the need for a standard on steel detachable link chains. In May 1951, a subcommittee of ASA Sectional Committee B29 was appointed with members from the agricultural implement industry and the steel detachable link chain industry to develop a standard for steel detachable link chains.

During the 1960 revision, certain sizes of chains and attachments were deleted from the Standard with the intent of eliminating those of low popularity that were also closely similar to other existing sizes, thereby strengthening the Standard. In addition, several popular chains, attachments, and couplers were added. Some attachment designs were slightly revised. The coupler and coupler pin designs were revised to the currently more popular style, which allows any link to be used either right-handed or left-handed.

This Standard establishes, in the main, only those dimensions that will provide for interchangeability of the chains in use without restricting the chain manufacturers in their overall design. The 1983 revision included the sprocket dimension controlling the surfaces that must properly engage or clear the chain. The 1994 edition updated the Standard to the current ANSI standards format and symbols covering chains. Number 45 and No. 67 were deleted from the Standard since they are no longer manufactured. The definition of Minimum Ultimate Tensile Strength (M.U.T.S.) was also updated.

In this edition, the symbols and sprocket information sections were revised to provide consistency throughout the consolidated B29.300 Standard.

B29.19 - Agricultural Roller Chains, Attachments, and Sprockets

Agricultural replacement roller chains, introduced around 1956, provide implement engineers with an upgrade from cast or steel detachable chains. These chains offer increased strength and durability, and can be used with the same sprockets.

The agricultural replacement roller chains are available in both drive series (A550 and A620) and conveyor series (CA550 and CA620). They have replaced No. 55 and No. 62 detachable chains in many applications and have found use in light-duty industrial conveyors.

The Standard establishes essentially only those dimensions that will provide for interchangeability of the chains in use without restricting the chain manufacturers in their overall designs.

The B29 Committee agrees that the CA550 and CA620 chains may be used on No. 55 and No. 62 detachable chain sprockets, respectively; however, the sprocket data included in this Standard is for sprockets designed specifically for CA550 and CA620 chains. The difference in sprocket design is necessary because of the difference in roller diameters.

The 1993 revision included updating to the current ANSI standards format and symbols covering chains and sprockets. Minimum Ultimate Tensile Strength (M.U.T.S.) was redefined.

The 1996 revision changed the name of the Standard from "A and CA550 and 620 Roller Chains, Attachments, and Sprockets" to "Agricultural Roller Chains, Attachments, and Sprockets." Also, two new chains for both drive series (A555 and A557) and conveyor series (CA555 and CA557), as well as several associated attachments, were added to the Standard.

In this edition, the sprocket tooth form was modified to be identical with the form used in the other two chains.

B29.25 - Open Barrel Steel Pintle-Type Conveyor Chains, Attachments, and Sprockets

The open barrel steel pintle chain was originally developed in 1962 for the agricultural implement industry. The original sizes were developed to run on the same sprockets as their detachable chain counterparts of ANSI B29.6. In later years, sizes were developed to accomodate industrial applications as well.

The steel pintle chain is primarily used as a conveyor chain and, in limited use, as a power transmission chain. Typical conveyor speeds are under 300 ft/min. Consult manufacturers for details.

The 1994 revision incorporated a restatement of the definition of Minimum Ultimate Tensile Strength (M.U.T.S.), and an addition of footnotes in Tables 3 and 4 regarding hole sizes in certain attachments.

In this edition, Tables 1 and 2 were combined for simplicity, and the sprocket tooth form was modified to be identical with the form used for the other two chains.

Suggestions for improvement of these three Standards are welcome. They should be sent to The American Society of Mechanical Engineers; Secretary, B29 Main Committee; Three Park Avenue; New York, NY 10016-5990.

ASME B29.6, ASME B29.19, and ASME 829.25 were approved as American National Standards on November 30, 1998.